The subject invention relates to a pedal assembly with a sensor that generates an electric signal for controlling a vehicle system. Specifically, the pedal assembly includes a multi-pole cylindrical magnet that rotates with pivotal pedal movement to generate a linear output signal varying with pedal deflection.
Pedal assemblies are used to control movement of a vehicle. Typically pedal assemblies include mechanical connections to the respective vehicle system that the pedal controls. For example, a mechanical connection for an accelerator pedal usually includes a bracket and cable-connect to an engine throttle. The rotary movement of the pedal is transferred to the engine throttle via the cable. The cable controls the position of the engine throttle based on the position of the pedal. Similar mechanical connections are used for brake and clutch pedals.
As vehicles incorporate more electrically control vehicle systems, attempts have been made to provide an electrical link between the pedal and the vehicle system to be controlled. Mechanical connections are often bulky and difficult to package within the limited space available in the vehicle. The components in the mechanical linkages are also subject to wear and can bind or stick causing the vehicle system to become inoperable. The electrical link eliminates the need for mechanical linkage parts and thus, reduces cost and increases packaging space for other vehicle components.
Some pedals incorporating electric control utilize contact sensors such as potentiometers to generate the control signal as the pedal pivots between various operational positions. One disadvantage with the use of contact sensors is that they tend to wear over time, which can affect the accuracy of the control signal.
Sometimes non-contact sensors such as Hall effect sensors are used to generate the control signal. An example of a pedal incorporating a non-contact type sensor for electric control is shown in U.S. Pat. No. 5,439,275. The pedal assembly includes a Hall Effect sensor used in combination with magnets mounted within a plunger to generate an output signal that varies according to pedal position. As the pedal is pivoted, the plunger moves in a linear direction with respect to the sensor resulting in a varying magnetic field. In such a configuration it is difficult to convert rotational pedal input movement into an accurate linear output from the sensor, which can be used to control the vehicle system.
Thus, it would be desirable to have an improved pedal assembly with a non-contact sensor that can use rotational pedal input to produce a linear output that corresponds to pedal deflection so that an accurate control signal can be used to control the corresponding vehicle system.
A pedal assembly for a motor vehicle is used to generate a control signal for a vehicle system. The pedal assembly includes a support mounted to a vehicle body structure and a pedal arm with an upper end pivotally mounted to the support for movement relative to the body structure and a lower end for supporting a pedal pad. The pedal arm is movable between a plurality of operational positions as a force is applied to the pedal pad. A magnet is mounted to the pedal arm for pivotal movement with the pedal arm. A non-contact sensor assembly is mounted adjacent to the magnet such that the sensor remains fixed relative to the pedal arm at all operational positions. The sensor generates an electric control signal for controlling the vehicle system as the pedal arm is moved between the operational positions. The signal varies in magnitude by the extent of angular rotation of the magnet relative to the sensor. Thus, the sensor converts rotational movement of the magnet to a linear output control signal that is used to control the vehicle system.
The sensor measures a varying magnetic field generated by the magnet as the pedal arm pivots between operational positions and generates a linear output voltage proportional pedal deflection. In the preferred embodiment, the magnet is a permanent magnet including multiple poles alternating between positive and negative orientations. The permanent magnet is preferably cylindrical in shape with each of the poles having a predetermined width with the poles alternating between positive and negative orientations about the circumference of the magnet.